Esters are among the most important and abundant functional groups in chemistry and they are widely found in food, pharmaceutical, flavor, and fine and bulk chemical industries. There are classical methods, e.g. reaction with carboxylic acid derivatives, carbonylation and the Tischenko reaction, which could be used to prepare ester compounds. The coupling of aldehydes with alcohols and coupling of two alcohols in the presence of external oxidants can also form esters. An alternative approach is the dehydrogenative coupling of two alcohols or aldehydes with alcohols with the release of H2.
Acceptorless dehydrogenative homo-coupling of alcohols have been reported however a need still exists for a catalytic process that allows for the chemoselective dehydrogenative cross-coupling of aldehydes with methanol to afford corresponding methyl esters in high yields and moderate selectivities.
The present invention addresses this need as well as others, which will become apparent from the following description and the appended claims.